مریم بشارتی

Abstract

  The supply chain is an integral concept in modern competition and business. In recent decades, the rise in competition has become a key issue in the market, prompting organizations to make significant changes not only in the nature and concept of competition but also in the structure and approach to competing with others. This transformation in the form and nature of competition can be observed and analyzed in both inter-organizational and inter-supply chain competition. Historically, organizations viewed their competitive strategies as centered around resource ownership and information confidentiality. However, in today's market, the definition of competition and success is rooted in cooperation, coordination among members, and the sharing of information and resources. Consequently, in recent decades, companies have sought opportunities to collaborate with their supply chain partners to ensure efficiency, responsiveness, and competitiveness within the supply chain. One of the ways to facilitate this cooperation and coordination is through coordination contracts, which can provide a competitive advantage to the supply chain.

This study, therefore, aims to coordinate and minimize the costs of a two-level multi-product supply chain consisting of a single supplier and multiple retailers under vendor-managed inventory (VMI) and cost-sharing contracts. The demand during the lead time is probabilistic, and the downstream supply chain members examined in this study are risk-averse, with varying levels of risk aversion, which is represented as a constraint in the mathematical model. The model also considers constraints on the warehouse space of each retailer and the credit limits for their purchases. The objective of the proposed mathematical model is to minimize the total supply chain costs by determining the optimal order points and reorder quantities for each product and each retailer. Numerical solutions to the model, obtained using GAMS software for various problem sizes, along with sensitivity analysis of key parameters and a case study in the construction industry, demonstrate that, based on the parameters of the coordination contracts, significant reductions in supply chain costs are achievable. Furthermore, the proposed model can lead to a solution with lower overall costs, while the impact of the risk aversion of supply chain members on costs is noteworthy, leading to higher holding costs, reduced shortage costs, and, ultimately, an increase in total supply chain costs.